This study was designed as a test of the serum lipid response and dietary adaptation to recommended daily inclusion of instant oats in an otherwise regular diet. Hypercholesterolemic adults were randomly assigned to a control or intervention group. Participants in the intervention group were given packages of instant oats and requested to eat two servings per day (approximately two ounces dry weight), substituting the oats for other carbohydrate foods in order to maintain baseline calorie intake and keep weight stable. Serum lipids were measured in blood collected by venipuncture at baseline, four weeks, and eight weeks. Baseline mean total cholesterol (TC) levels were 6.56 mmol/L and 6.39 mmol/L for intervention and control groups, respectively. After eight weeks, mean serum total cholesterol of the intervention group was lower by -0.40 mmol/L, and mean net difference in TC between the two groups was 0.32 mmol/L (95% CI: 0.09, 0.54). Low-density lipoprotein-cholesterol was similarly reduced with mean net difference of 0.25 mmol/L (95% CI: 0.02, 0.48) between the two groups. Mean soluble fiber intake increased along with slight self-imposed reductions in mean total fat, saturated fat, and dietary cholesterol intake in the intervention group. Neither group changed mean body weight. Daily inclusion of two ounces of oats appeared to facilitate reduction of serum total cholesterol and LDL-C in these hyperlipidemic individuals.